Find the greatest common factor for the group of numbers. 12 , 28 , 24

The greatest common factor, or GCF, is quite self-explanatory. Between two numbers, you have to find the greatest number that can be divided by both numbers without any remainder. This is useful in solving addition and subtraction operations involving fractions. The technique to do this is to place the numbers to the right. Then, place the factors to the left. I'm gonna show the solution so that you can understand better.

  4   |   12    28    24
       
       |     3     7      6
       

Since all numbers can be divided by 4, you place it on the left side. Then, place the quotients on the next row below. Since, there is no more common factor, it ends with the 2nd row. Then, multiply all the left numbers with the numbers in the very last column.

GCF = 4×3×7×6
GCF = 504